Re: Mysqld 3.23.56 crash on concurrent ALTER TABLE and FLUSH TABLE

Fred,

> Oops, my mistake. Even so, it shouldn't crash even with those queries.

Certainly not.  We are investigating it further and I will be adding a 
bug report for this.  Thank you for the test case!
 
> > ALTER TABLE $basetable UNION=($union);
> With your change I am still seeing crashes within seconds. I started
> with a clean database (i.e. no 'test' database), just to be sure.

I will test it against 3.23.56 and see if I can repeat it with that 
version.
 
> I'm not sure that the stack dump helps much, because it is slightly
> different each time. Whenever I checked the cause of the bus error, the
> pattern 0x8f8f8f8f was always there though, so memory got corrupted.

Any information is helpful, of course.
 
> Can I send the core dump(s) somewhere? Are they of any use for you?

You can ftp them to ftp://support.mysql.com/pub/mysql/secret if you 
like, but it may not be necessary provided we can continue to repeat 
the crash.

As I can very easily repeat the problem if the threads are operating on 
the same table, it should only be necessary if I still cannot cause it 
to fail when they are not using the same table.  Even so, it is always 
possible that these are caused by the same issue.

I will add the bug report after some more testing.  Again, thank you for 
reporting this and for providing a good test case.

Best regards,
-- 
Dean Ellis, Support Engineer & Software Developer
MySQL AB, www.mysql.com

Want to swim with the dolphins? (April 14-16, 2004)
http://www.mysql.com/uc2004/


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